title: Psychosocial factors and shoulder symptom development among workers.
abstract: BACKGROUND
  Shoulder injuries are a common cause of pain and discomfort. Many work-related factors have been associated with the onset of shoulder symptoms. The psychosocial concepts in the demand-control model have been studied in association with musculoskeletal symptoms but with heterogeneous findings. The purpose of this study was to assess the relationship between the psychosocial concepts of the demand-control model and the incidence of shoulder symptoms in a working population.
  
  
  METHODS
  After following 424 subjects for approximately 1 year, 85 incident cases were identified from self-reported data. Cox proportional hazards modeling was used to assess the associations between shoulder symptoms and demand-control model quadrants.
  
  
  RESULTS
  Cases were more likely to be female and report other upper extremity symptoms at baseline (P < 0.05). From the hazard models, being in either a passive or high strain job quadrant was associated with the incidence of shoulder symptoms. Hazard ratios were 2.17, 95% CI 1.02-4.66 and 2.19, 95% CI 1.08-4.42, respectively.
  
  
  CONCLUSIONS
  Using self-reporting to determine demand-control quadrants was successful in identifying subjects at risk of developing work-related shoulder symptoms. Research is needed to determine if this relationship holds with clinically diagnosed shoulder and other upper extremity musculoskeletal disorders. This may be part of a simple tool for assessing risk of developing these UEMSDs.
authors.affiliation: Safety & Health Assessment and Research for Prevention (SHARP), Washington State Department of Labor & Industries, Olympia, Washington, USA. smcb235@lni.wa.gov
authors.forename: Caroline K
authors.initials: CK
authors.lastname: Smith
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Silverstein
authors.forename: Z Joyce
authors.initials: ZJ
authors.lastname: Fan
authors.forename: Stephen
authors.initials: S
authors.lastname: Bao
authors.forename: Peter W
authors.initials: PW
authors.lastname: Johnson
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007389:Internal-External Control; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012782:Shoulder / Q000503:physiopathology; D000070599:Shoulder Injuries; D011795:Surveys and Questionnaires; D016526:Workload / Q000523:psychology*; D017132:Workplace / Q000458:organization & administration; D055815:Young Adult